Figure 2.

Formation of the mouse skull. (A–C) Histological images of developing mouse embryos showing formation of bone (magenta stained by alizarin red) and cartilage (stained by alcian blue) of the embryonic skull. (A) lateral view of embryonic mouse head at embryonic day 14.5 (E14.5) showing site of initial ossification of the frontal bone of the cranial vault (red arrow) and skull cartilage; (B) at E15.5, the forming frontal and parietal bones are clearly visible and the ossification of the interparietal bone is beginning (arrow); (C) By E17.5, the interparietal is well formed and other bones of the skull are clearly visible. (D) 3D reconstruction of micro computed tomography image of the mouse skull at birth (P0) colored to indicate the placement and level of maturity of all skull bones. (E) Adult mouse skull colored to show relative position of skull bones.